Dopamine, which is represented by formula (II): ##STR2## wherein R.sup.3 is a hydrogen atom; and dobutamine, which is represented by the above formula (II) wherein R.sup.3 is a group, ##STR3## have been used for the treatment of, for example, hypotension, cardiac circulatory insufficiency and cardinogenic shock. However, since each of these compounds has a free catechol group and is scarcely absorbed when administered orally or percutaneously, the administration of them is restricted to the continuous intravenous way.
Recently, ibopamine represented by formula (III): ##STR4## has been developed as a drug which exerts a dopamine-like effect and can be orally administered (cf. U.S. Pat. Nos. 4,218,470 and 4,302,471). However this compound is still unsatisfactory in sustained effect and it is reported that the half-life of this compound in plasma is 1.54 hour [cf. E. Lodola et al; Arzneim.-Forsch./Drug Res., 36(1), 345-348 (1986)]. It is further reported that the effect of ibopamine on improvement of the circulation, when evaluated by the cardiac coefficient, sustains 3 to 6 hours [cf. SOL I. Rajifer et al.; Circulation, 73, 740-748 (1986)].
Recently, further attempts have been made to develop a preparation capable of gradually releasing a drug in the blood for a prolonged period of time so as to improve the persistence of the effect of the drug. For example, U.S. Pat. No. 4,581,225 discloses a sustained release nasal preparation which comprises a catechol amine (for example, dobutamine), an emulsifier, a dispersant and an agent rendering the drug slowly released such as oleic acid, linolic acid or an ester thereof. Further, Okumura et al. have studied on the application of dopamine hydrochloride to the skin and reported that the use of a 5% aqueous solution of glyceryl monocaprylate can elevate the percutaneous penetration rate of dopamine hydrochloride to a level 34 times as high as that achieved by using dopamine hydrochloride alone [cf. Chem. Pharm Bull., 37(5), 1375-1378 (1989)]. In the practical clinical application, however, it is preferable to establish a higher skin permeability. There is an additional problem, furthermore, that dopamine hydrochloride is highly irritative to the skin and causes skin damage if it can be percutaneously absorbed. Therefore, this compound is unsuitable for practical application.
Other known dopamine derivatives, which might exert the dopamine- like effects, include those synthesized by introducing variuos substituents into the catechol and/or amino group [cf. C. Casagrande et al.; Arzneim.-Forsch./Drug Res., 36(2), 291-303 (1986)].